Tru64 - Linux transfers

I have a need to transfer a large amount of data between a Tru64 server (let's call it NODE_TRU) and a Linux server (NODE_LIN) and am finding a huge difference in pulling in one direction vs. the other.

Before messing around with any Oracle Net settings, I thought I'd first validate transfer rates node-to-node, using sftp. NODE_TRU is running Tru64 5.1 and is a 64bit GS1280 4 x 16, using SAN attached storage. Concurrent transfers were tested using 500 MB files on separate filesystems, each created using "dd" off /dev/zero. NODE_LIN is running RHEL 4.1 and is a 64bit 3850 quadcore 2 x 32, using SAN attached storage (EMC raw with ASM). The connection between the 2 is a Gb line. Here are the results of my testing so far, using 1, 2, 3, and 4 concurrent transfers:

On NODE_TRU we increased tcp_sendspace and tcp_recvspace from 61,440 to 1,048,576. On NODE_LIN we increased net.ipv4.tcp_rmem from 4096 87380 174760 to 4096 87380 16777216, net.ipv4.tcp_wmem from 4096 16384 131072 to 4096 65536 16777216, and both net.core.rmem_max and net.core.wmem_max from 262,144 to 16,777,216. The above tests were done after these parameter changes and unfortunately I only tested NODE_TRU Put to NODE_LIN before these changes (no real differences found in this transfer with the changes in place).

Are those the appropriate kernel changes to basically open the flood gates between the 2 servers? This is all in preparation for a huge transfer from NODE_TRU to NODE_LIN, so any increase in transfer rate will help greatly.